premix oil

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proppastie

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So it seems the low flash point is better? If so why not outboard motor oil?
 

Armilite

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So it seems the low flash point is better? If so why not outboard motor oil?
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They all Burn up, Full Synthetics just give better Lubrication for Higher Endurance. They can be used at 80:1 to 100:1 Ratios, so less carbon build up. Pistons, Melt on the Sides to cause Seizures from Friction Heat Build up. Low Flash Point Oils burn off to quick for High Endurance Engines. Burnt Holes on Piston Tops is from wrong Jetting, running them to lean, Bad Case Seals, Bad Carb Boots. Pitting on Piston tops or Broken Pistons & Rings is from Detonation.

So anything you can do to make them run Cooler with Help them to live longer!

Rotaxs with to tight of Belt on Belt Drives have Melted the Plastic Crank Bearing Retainers, front Seals. That Stator on the other end is making Heat also which your Crank acts as a Heat Sink so affects the rear Case Seal. The Higher the Rpms you turn your engine the Hotter your Bearings will get. It's not the Bearing Balls or Rollers that Fail, it's the Cages and Retainers that Fail. That's WHY, the Cageless Upper Rod Bearings are the best. Steel Retainers are good, by they Rust eventually, Nylon Retainers are better. If you use good Oil and fly a lot to keep Oil on them, and pickle the engine right when not using it, the Steel Retainers will last a long time. Nylon doesn't Rust and has a High Melt tempeture like 500F.
 

Jay Dub

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I know this thread is 3 years old but I want to resurrect it. I have a freshly rebuilt 447 I hope to put on a Kolb Firestar I'm building so oil is on my mind.

Back in the early 90's I had a CGS Hawk with a 447 on it that I mostly used the Pennzoil "Air Cooled" oil. It coked up the pistons and rings pretty badly. After talking with a snowmobile mechanic he swore by Citgo 2 cycle oil and I switched. While it still carboned, it wasn't nearly as bad as the Pennzoil "air cooled" variety. I see Citgo does make an aircooled 2 cycle oil but I'm not sure where I can find that. I had about 500 hobbs hours on that engine when I sold it (I put about 450 of those on it myself and a buddy put the other 50 or so on it).

A few years ago I bought a new Stihl weedeater. They doubled the warranty if I bought a pack of their Ultra HP full synthetic oil which was new at the time. I have run it in both the weedeater and a Stihl MS660 saw ever since. It seems to run clean and I haven't noticed any corrosion inside, even while living in Michigan not far from Lake Michigan (high humidity).

Stihl products are forced air cooled just like the Rotax 447. The Stihl oil isn't cheap but isn't too expensive and is readily available. Would there be some reason I shouldn't use it in a 447?

I know about 16 years ago taking my dad's early 80's Stihl saws to an Amish chainsaw shop (in Ohio) in 2005, the Amish mechanic said while looking into the exhaust port, "you run Stihl oil I can tell." My dad always used the orange bottle of Stihl HP oil (not the new ultra). That saw had over 20 years of a lot of use without a rebuild. My dad has burned 6-8 chord (not face chords either) of firewood a year every year and that was his main saw. The Amish guy said the Stihl oil burns cleaner and has less deposits. That was before the synthetic HP oil. He said he could usually tell you what brand oil was used in saws when he took them apart. Many left tell-tale deposits and wear patterns. I never forgot that even though I've often thought there's probably just 1 or 2 plants that even make 2 cycle oils and just repackage them for different contracts.

Jay
 

Jsample40

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The 2 cycle premix oil I used successfully for many years in small aircraft engines was made for Yamaha products, called "Yamalube R". Never had any engine damage such as seized or damaged pistons, etc. Today's version is known as "Yamalube 2R"... and is used by the Yamaha Racing team. In my opinion, Y2R or Amsoil Interceptor oil will produce optimum results in 2 cycle engine applications at between 40:1 or 50:1 mix ratios (depending on manufacturer's recommendations).
Jay Sample
 

Jsample40

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So it seems the low flash point is better? If so why not outboard motor oil?
Outboard oil is generally used in water cooled equipment (ie: water cooled outboards), and is designed for lower cylinder head temps. Using outboard oil in air cooled 2 cycle engines will likely result in more carbon fouling and buildup on plugs, pistons, and rings, than 2 cycle oil which is designed for use in engines with higher cylinder head temps.
Jay Sample
 

Armilite

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The flashpoint temperature is better the higher it is. Here's what happens: When the
gas/oil adheres to the cylinder inside then the gasoline immediately evaporates off (once the engine has reached normal operating temp) and leaves the oil. The flashpoint temp is the temperature at which the oil burns off at its surface. Only some burns off though since the molecules closest to the cylinder are cooler since the cylinder is much cooler (100C and up) than the combustion temperature. So the higher the flashpoint, the less oil burns off and the more oil is left to protect the top end (cylinder, piston, rings). That is why it is listed in datasheets for oils and why I included it in my formula.

Also, a lower flash point oil (ie: mineral oils) will lower the octane of the gasoline so the higher the flashpoint, the better. So if your engine is high compression and you are using high octane gas then you should try using an oil with a higher flash point (full or part synthetic) in order to avoid any possibility of detonation. In the old days, when all of the two-strokes were developed, they all used Castrol petroleum oil at a 20:1 ratio and found that 92 octane gas had the octane reduced to 72 with the presence of that much oil.

A research paper used a 167cc 4 stroke engine with 6.6 compression ratio to a record
250ºC at the piston edge @ 5000 RPM which could be projected to be 300ºC at 9000
RPM. The rings will be a little cooler since they are the thermal conduit between the
piston and the cooler cylinder, and the cylinder is gradually cooler with distance down from its top. So if we guess at the average ring temperature as being 150ºC on air-cooled engines then we need to calculate for an engine oil viscosity at that temp for comparison of oils for use in air cooled engines. So for the oils that have their 40ºC and 100ºC viscosities listed then the 150ºC viscosity is calculated from an online calculator. For water-cooled engines, my calculator just uses the listed 100ºC viscosity in the formula. Cylinders that are chromed are slicker and need less oil. All cylinder liners (sleeves) are about a class 40 grey cast iron composition. The hardness can vary greatly depending on the kind of heat-treating which was used. Steel is never used in cylinder liner composition.

What is the Flash Point of your Stihl Oils?

Brand Temp
---------------------------------------
Castor Oil 2 Stroke 445°F
Maxima Castor 927 420°F
Bel Ray H1R 417.2°F
XPS BRP/Castrol 350°F SKIDOO
SUPER TECH 330°F (Walmart)

MAG 1 Synthetic 329°F (Walmart)

Motul 800 285°F
Maxima Super M 280°F
Yamalube 2R 255°F YAMAHA
Motul Bio 2T 255°F
Amsoil Saber Outboard 248°F
Maxima Formula K2 240 F
Amsoil Saber Pro 237°F
Red Line All Sport 230°F
Motorex Cross Power 2T 230°F
Hirth Blue Max 230°F
Red Line Two Racing 221°F
Maxima Super M Injector 220°F
Maxima Castor Oil 927 215°F
Pennzoil Multi 212°F
HUSQVARNA 2 Stroke 210°F
Bel-Ray MC1 208°F
Golden Spectro 2T 205°F
Mobil 2 Stroke Oil 204.8°F
Red Line Smokeless 201.2°F
Amsoil Dominator 198°F
Spectro "Golden" SX 196°F
Bel-Ray Si7 194°F
Castrol 2T 194°F
Spectro "Platinum" SX 191°F
Motul 710 190°F
Amsoil Interceptor 187°F What Rotax Rick uses in his 670's 40:1.
Golden Spectro Injector 187°F
Lucas Semi-Synthetic 182°F
Maxima Bio 2T 180°F
Valvoline 2 Stroke 172°F
Torco GP-7 165.2°F
Castrol Power RS 163°F
 
Last edited:

Yellowhammer

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I choose the Amsoil oil because of its supposed ability to prevent carbon buildup. I will keep this group posted on my findings.
I run 100LL because i dont know anything about pump gas down at the station.
I didn't think i would like the 582, but so far haven't had a reason not to.

Amsoil the best. Keep using it If it aint broke dont fix it.
 

Jay Dub

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After I posted here a bit up the page, I did a lot more reading and learning. A lot of the older 2 cycle oils were fairly similar. As I read and studied the Stihl ultra oil isn't rated that highly as it was made for double duty in both their 2 stroke and "4 mix" engines.

The most impressive 2 stroke premix oil for air cooled engines (I have a fresh Rotax 447) to me is Red Armor sold under the Echo or Shindaiwa brands. It's available not just at local power equipment dealers but also at hardware stores and home depot. I read online it is made by Spectro oils but I have no way to confirm that. It isn't cheap but the anti carbon buildup is impressive as well as the stabilizing effects are also impressive. Looking at photos of engines torn down that used it also shows good coverage and corrosion protection.

Red Armor is a high detergent oil that doesn't carbon up pistons nor exhaust ports. It also contains fuel stabilizers so gas doesn't go stale quickly (non ethanol supposedly lasts 2 years without going stale if it is stored in a non-vented container out of sunlight). Some testing done by echo had a piece of equipment with several hundred hours on it and no ring sticking and the exhaust port wasn't carboned up and neither was the piston crown nor skirts but one always has to wonder how the tests were conducted. It actually removes built up carbon on equipment that used other oils in the past. You can find photos online of tests people have done with this oil with photos and videos and borescope images.

TC was the old rating "back in the day" then for water cooled 2 strokes, like marine engines, used a TC-W, TC-W2 and now TC-W3 ratings. If you look into it, JASO, a Japanese testing company, rates oils supplied to them. The current best rating is "FD" then lesser rating but still good is FC, then lower is FB, then last is FA oils. Red Armor and several other newer offerings (both synthetic and dino based) carry the FD rating, while a lot of the older dino based products carry an FA-FC rating.

Amsoil appears to also offer good FD rated oils, however I'm just not into "multi level marketing" company products. If you choose to sell your product via MLM, I'm just not interested as I've had too many friends get taken into the Scamway MLM and try to get me into it. A lot of folks run their 2 stroke engines with Amsoil mixed at 100:1 ratio and have no trouble. Others have burned up their stuff at that ratio. To each their own.

It does appear 2 stroke oils have gotten much better since the Rotax recommended "Pennzoil for air cooled" oil (early 90's) which coked up rings and ports badly in my experience at 50:1, just not as badly as the TC-W oils did at that time.

Jay
 

kool69sporty

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May 12, 2019
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Jay W, my read on the Stihl High Performance ULTRA full Synthetic 2 stroke says flash point: 428 deg F. That ranks high on your list. What am I overlooking if it "isn't rated that highly" ?
 

TLAR

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I just love it when people learn new stuff

It is a new era when information is so readily available, key word search will help the drill down typing madness.

I have a Stihl chainsaw that will idle imagine that
 

reo12

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Jan 15, 2021
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I have been told lead is bad for two-strokes, fouls the plug. Temperature issue? Course it can foul the plugs in my Lycoming too,
I ran 100LL in a 2 stroke when I had to for long flights. Always had shorter plug life when I used 100LL. Sometimes the lead deposits could be seen as bumps on the electrodes. One time it bridged the gap. The bridged gap occurrence was not after all that many hours. I never ran more than 10 gallons of 100LL before being back home and using auto premium.
 

reo12

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Jan 15, 2021
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Seems I heard on some 2-smoke forum that oil actually burns hotter than gasoline.
Modern petroleum base 2 stroke oil has solvents in it to improve mixing. (some of us remember when it was the viscosity of motor oil) It has a lower octane than gasoline. According to a Shell lubrication specialist we had at a forum once - adding oil to gasoline lowers octane 2- 4 octane points. Storing fuel in polyethylene fuel tanks can cause a loss of octane in the range of 3 octane points per month as the polyethylene is permeable to the octane improving agents in the fuel.
 
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